Graeme wrote in
4.51:

And I can imagine Guy's reaction :{)


That's meant to be a 'tached smile BTW ;-)

Just zis Guy, you know? wrote:

[ ... ]

...actually ABS doesn't really affect stopping distances. It allows
you to steer while braking.

I think it does - it certainly helps prevent skidding in wet weather, even
if that is all it does.


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Just zis Guy, you know? wrote:

I don't think anyone is immune to risk compensation, although some
people have a more realistic view of the merits of various safety aids
than others. The comment refers to research done on drivers with and
without ABS and seatbelts, which showed that they drove faster and
less safely when using those devices.

See Risk by John Adams.


Interesting piece on Radio 4 Today this morning about "childproof containers".
There are 25,000 incidents a year involving children. The person interviewed
said the problem was people thought them childproof when in fact they are only
child resistant. Consequence is they keep "childproof" bottles of bleach etc
in places which are convenient but accessible to children rather than put
away. The perception of "childproofness" has therefore increased the risk to
children over ordinary containers which most people would put somewhere safe
with children around.

Tony

Mark Tranchant wrote:
Velvet wrote:

So in my experience (and I do speak from experience) when you avoid a
skid in a non-abs car and the one in front does have it, you end up
braking slower, with obvious consequences if you're close enough...


You mean "too close".


Indeed ;-)


--


Velvet

Just zis Guy, you know? wrote:

On Sun, 20 Jun 2004 22:37:33 GMT, Velvet
wrote in message :


On the other hand, they drive less carefully when protected by
airbags, abs and seatbelts.


Not all of them do, ta :-)


I don't think anyone is immune to risk compensation, although some
people have a more realistic view of the merits of various safety aids
than others. The comment refers to research done on drivers with and
without ABS and seatbelts, which showed that they drove faster and
less safely when using those devices.

See Risk by John Adams.


I don't rely on ABS to stop me quicker - I
use it to even out the fact that the car in front probably has it and
will stop quicker than I can if I don't have it...


Er, actually ABS doesn't really affect stopping distances. It allows
you to steer while braking.

Not convinced by this :-)



So it's not quite as clear cut that all the extra safety stuff makes
people drive less carefully :-)


It is, though. The taxi driver ABS trial was a near-perfect
double-blind study and it showed that those driving ABS equipped cars
accelerated harder, braked harder, drove faster and followed closer.

Guy

But I'm not a taxi driver!

--


Velvet

Velvet wrote:

Er, actually ABS doesn't really affect stopping distances. It allows
you to steer while braking.

Not convinced by this :-)

It is simplistic, of course; the reality is that given perfect braking
technique a driver can stop at least as quickly in a non-ABS car; ABS makes
no difference to the grip of the tyres or the power of the brakes. A really
expert driver can theoretically stop shorter in a non-ABS car, because ABS
senses wheel slip, while a really expert driver won't allow that to happen.
In practice few drivers have perfect braking technique, but as previously
posted, on a dry road it is close to impossible to get the ABS even to cut
in on my car - it grips too well. So, ABS prevents some skids due to poor
braking technique, and allows steering while braking with less risk of loss
of control, but it doesn't really improve the braking performance of the
car.

It's also a mistake to rely on it in ice or on gravel. If all wheels lock,
the ABS thinks you've stopped and cuts out. Don't try this at home!

So, it's important not to think (or to allow people to think) "ABS stops you
quicker", because (a) technically it doesn't and (b) relying on that for
safety margin is a Very Bad Idea.

The taxi driver ABS trial was a near-perfect
double-blind study and it showed that those driving ABS equipped cars
accelerated harder, braked harder, drove faster and followed closer.

But I'm not a taxi driver!

Similar studies have been done on a wide range of drivers and a wide range
of safety devices, the conclusion is always the same.

Think: "Nobody believes in risk compensation, that's why it happens."

--
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

Just zis Guy, you know? wrote:

Velvet wrote:


Er, actually ABS doesn't really affect stopping distances. It allows
you to steer while braking.


Not convinced by this :-)


It is simplistic, of course; the reality is that given perfect braking
technique a driver can stop at least as quickly in a non-ABS car; ABS makes
no difference to the grip of the tyres or the power of the brakes. A really
expert driver can theoretically stop shorter in a non-ABS car, because ABS
senses wheel slip, while a really expert driver won't allow that to happen.
In practice few drivers have perfect braking technique, but as previously
posted, on a dry road it is close to impossible to get the ABS even to cut
in on my car - it grips too well. So, ABS prevents some skids due to poor
braking technique, and allows steering while braking with less risk of loss
of control, but it doesn't really improve the braking performance of the
car.

It's also a mistake to rely on it in ice or on gravel. If all wheels lock,
the ABS thinks you've stopped and cuts out. Don't try this at home!

So, it's important not to think (or to allow people to think) "ABS stops you
quicker", because (a) technically it doesn't and (b) relying on that for
safety margin is a Very Bad Idea.


I think we're kindof in agreement here. My point was that people aren't
all that likely to be braking as well as ABS would if you apply it
properly - people (myself included) either tend to overbrake (and skid
if no abs) or underbrake (abs or no, they'll not stop as fast as if they
overbraked with abs).

I've braked on ice with ABS - it was interesting and I'm glad I did it
gently. Stopped car from sliding but took a VERY long time to stop the
car. On the other hand, braked once on snow and had to do a very
abs-like recovery of it to stop in time (downhill on snow toward T
junction).

I know if I tromp on my brakes then I'll stop quicker than if I brake
with no ABS, because I tend to the underbrake not overbrake to avoid the
skid. Ergo, for me, ABS *will* mean I'll stop in a shorter distance.

I don't drive any closer (or further away, it has to be said) than
pre-ABS. Some of my cars have had it, some haven't. I've only once had
to tromp on the brakes and could have done with ABS (I didn't lock the
wheels so probably underbraked, with ABS I'm much more willing to tromp
very hard since I know it'll help prevent the skid) - but given I've
never actually needed to, it's not changed the way I drive - I don't
think the ABS will save me, cos actually I've no idea if it would in any
given situation or not, and I'm not *really* all that keen on seeking
out instances when I'll find out...
--


Velvet

Tony Raven wrote:

Interesting piece on Radio 4 Today this morning about "childproof containers".
There are 25,000 incidents a year involving children.

I thought it was BeHit who put 25000 children into containers.

John B

On Mon, 21 Jun 2004 11:05:32 +0100, "Just zis Guy, you know?"
wrote (more or less):

On Mon, 21 Jun 2004 10:42:13 +0100, "Grant Mason"
wrote in message :

Er, actually ABS doesn't really affect stopping distances.

Yes it does.
http://www-nrd.nhtsa.dot.gov/vrtc/ca...99-01-1287.pdf
"For most stopping maneuvers, made on most test surfaces, ABS-assisted panic
stops were found to be shorter than those made with best effort or full
pedal applications with the ABS disabled"

Because people don't know how to brake. But the statement was overly
simplistic, of course.

ABS does not increase the power of the brakes, and does not increase
the coefficient of friction. All it does is make it less likely that
the driver will lock the wheels.

With abs, if one wheel is about to lock, the other three wheels can
remain braking.

To avoid one wheel locking up with non-abs brakes, all four wheels
have to stop braking.



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On Mon, 21 Jun 2004 19:32:55 +0100, Gawnsoft
wrote in message
:

With abs, if one wheel is about to lock, the other three wheels can
remain braking.
To avoid one wheel locking up with non-abs brakes, all four wheels
have to stop braking.

Indeed. But that's only relevant in specific conditions. I've
already said it: ABS does not increase the braking performance of the
car. It does compensate in some degree for poor technique, but even
then you can fool it. Relying on ABS to "help you stop quicker" is
stupid, and allowing people to think that's what it does is Not Smart.

Guy
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